Bending machine



Aug. 21, 1956 L. D. GILBERT 2,759,515

BENDING MACHINE- Filed April 2, 1951 7 Sheets-Sheet l //V VE/V TOR Lloyd 0. Gilbert Decd.

y David 0. ol/plianr, Jr. Adms/r.

HIS AT TOEWEYS L. D. GILBERT BENDING MACHINE Aug. 21, 1956 7 Shee tS-Sheet 2 Filed April 2, l95l INVENTOR. Lloyp D. 6i/ berf, Deca'. y Dov/0' 0. 0/1p/1anl. Jr. Admsfr.

HIS ATTORNEYS g- 1956 L. D. GILBERT 2,759,515

BENDING MACHINE Filed April 2, 1951 7 Sheets-Sheet 3 INVENTOR. Lloyd 0. GI-Iberf', Dec'd.

[2| David D. Ohio/2on7; Jr. Adms/r.

Hi5 ATTORNEYS Aug. 21, 1956 L. D. GILBERT BENDING MACHINE 7 Sheets-Sheet 4 Filed April 2, 1951 INVENTOR. L/oy d 0. GZf/bert Decd. By Dav/0' 0- 0/40/7011)! Adms/r.

fi wf w HIS ATTORNEYS 1956 Y L. D. GILBERT 2,759,515

BENDING MACHINE Filed April 2, l95l 7 Sheets-Sheet 5 N INVENTOR).

Lloyd 0. 61/berl, Dec'd.

B David 0. oli nanr, Jr. Mm's/r.

HIS ATTORNEYS Aug. 21, 1956 L D. GILBERT 2,759,515

' BENDING MACHINE Filed April 2, 1951 7 Sheds-Sheet s INVENTOR. Lloyd 0- GI/berI, Decd. BY David 0. OIIpbanI, Jr. Admsfr.

HIS ATTORNEYS BENDING MACHINE Filed April 2, 1951 7 Sheets-Sheet 7 //v VEA/ 70/? Lloyd 0. G/Iberf, Decd.

5y Daw'd 0. 0/60/7001; Jr Adms/r.

(17,641, 9- 75M ATTOfi/VE rs United States Patent BENDING MACHINE Lloyd D. Gilbert, deceased, late of Alameda, Califl, by David D. Oliphant, Jr., administrator, Oakland, Calif., assignor to Pacific Coast Engineering Company, Alameda, Calif., a corporation Application April 2, 1951, Serial No. 218,756

16 Claims. (Cl. 153-61) The present invention relates to bending machines and more particularly to that type wherein bending is accom plished by the use of bending rolls.

In machines of this character, a plurality of rolls, usually three in number, are mounted for rotation to simultaneously act upon a sheet of metal fed between them, and by their joint effect, produce an arcuate bend in the sheet. The rolls are adjustable, relatively speaking, to alter the radius of bend, and where the sheet metal is of too great a thickness for a particular machine to effect the proper degree of curvature in a single operation, the end result may be accomplished by successive adjustments of the rolls in the direction of sharper curvatures.

The removal of the work, following the bending of a sheet to a form which may not otherwise be removed, necessitates the temporary removal of an end support for that roll about which the work has been formed, which is usually the upper roll, to permit the work to be slipped off endwise of the roll.

In prior art machines, the operations were attended with an expenditure of much time and eifort, and the adjustment of the rolls was slow and largely a matter of approximation and guess-work.

Among the objects of the present invention are,

1. To provide a novel and improved bending machine;

2. To provide a novel and improved bending machine capable of increased working speed;

3. To provide a novel and improved bending machine which is hydraulically powered;

4. To provide a novel and improved bending machine in which stresses on the roll supports have been balanced and have become a negligible factor in the operation of the machine;

5. To provide a novel and improved bending machine in which the rollers may be removed or replaced with a minimum of time and effort and Without necessitating dismantling of the entire machine.

6. To provide a novel and improved bending machine in which the rollers may be quickly and accurately adjusted for spacing, and quickly and accurately re-set to a previous known adjustment.

7. To provide a novel and improved bending machine in which the rollers may be accurately adjusted for a coming operation.

8. To provide a novel and improved bending machine in which the end support for the upper roll may be quickly removed, even in an elevated position to facilitate removal of the work from the upper roll;

9. To provide a novel and improved bending machine in which the upper roll may be tilted without adding strain to the bearings;

10. To provide a novel and improved bending machine in which the end support for the upper roll may be removed without disturbing the end bearing at that point;

11. To provide a novel and improved bending machine in which all machine movements are under the .control of a single operator from an operators station;

12. To provide a novel and improved bending machine of simplified and rugged construction.

Additional objects of the invention will be brought out in the following description of a preferred embodiment of the same taken in conjunction with the accompanying drawings Wherein Figure 1 is a three-dimentional view of a machine constructed in accordance with the present invention;

Figure 2 is an elevational view of the machine of Figure 1;

Figure 3 is a plan view, partly in section, of the machine of Figure 1, partly dismantled;

Figure 4 is an elevational View, partly in section, of the outer end support and adjusting mechanism for the upper roll;

Figure 5 is an end view of the apparatus of Figure 3;

Figure 6 is a view corresponding to that of Figure 3 but showing the end support for the upper roll removed to permit of the removal of work formed about such roll;

Figure 7 is an end view in elevation of the apparatus of Figure 6;

Figure 8 is a view in section through the machine, taken in the plane 88 of Figure 2, showing the support for the inner ends of the rolls;

Figure 9 is an elevational view, partly in section, of the inner end of the machine of Figure 2 depicting the drive to the lower rolls and the manner of maintaining the upper roll in tilted position;

Figure 10 is a front elevational view of the gear drive to the lower rolls of the machine;

Figure 11 is a view in elevation, depicting the operators station and that feature of the machine which serves to indicate the adjustment of the upper roll;

Figure 12 is a front elevational view of the indicating elements from which an operator may determine both the actual and relative adjustment of the ends of the upper roll;

Figure 13 is a side elevational view of the indicating means of Figure 12; and

Figure 14 illustrates the hydraulic system involved.

Referring to the drawings for details of construction of the machine in its preferred form, the operating components thereof are supported on a base frame 1 comprising a pair of longitudinal side members 3, 5 joined by end members 7, 9, such frame members being preferably constructed of heavy I-beams' welded end to end to form the frame. The frame may be mounted on a suitable raised wall foundation or disposed around a floor pit to provide room for certain of the operating components as well as to offer accessibility to the under side of the machine for inspection and such servicing as may be necessary.

The particular machine under consideration provides for a pair of lower rolls 11 and 13 disposed in a common horizontal plane, and an upper roll 15 located symmetrically with respect to the two lower rolls.

The lower rolls are disposed in a cradle formed by the base frame and a pair of cradle end castings 17, 19 disposed transversely of the base frame and aflixed thereto. Each of these cradle end castings includes semicylindrical bearing seats 21 laterally spaced and symmetrically disposed with respect to the center line of the casting, with each of said bearing seats inclined at an angle of substantially 60 degrees with such center line and serving as mountings for cylindrical bearings or bushings 23 in which the lower rolls are journalled.

Integrally cast as a part of each cradle end casting and depending therefrom is a cylinder 25 formed with a neck 27 extending upwardly between the cradle bearings. In each of these cylinders is disposed a piston 29 having a piston rod 31 extending upwardly for use in connection with supporting one end of the upper roll 1 2 an a. pistan rod. 3. extending downwardly through the lower end of the cylinder, the cylinder being sealed at this end by a closure 35. Threadedly secured to the end of the uPPfil piston rod is a cross-head 3'7 involving a pair of parallel arms 39. having aligned holes for receptign of a pin 41 upon which may pivot a bearing block 4;} which is formed with a complementary groove 44 along its lower surface to receive and seat said pin. Such bearing block carries a bearing 45 in which is journalled one end of' the upper roll.

This bearing block is pivotally held on the pin by a latch comprising a pair of side links 47, each rotatively mounted at one end on an extremity of the pin- 41, and connected. together at their other ends by a cross-bar 49, the links being of sufiicient length to permit the cross-bar to be swung into surface contact with the upper surface of the bearingblock, and for this purpose, both the lower surface of the cross-bar and the upper surface of the bearing block are contoured on an arc whose center of curvature coincides with the axis of the. pin. Suchtype of bearing mounting permits of tilting. of the upper roll about an end support without altering the. relationship of'the bearing to the roll and without stressing the hearing.

A pipe connection 51 to the upper end of the cylinder and a similar connection 52 to the lower end, permits of selective feed of hydraulic power to either end, with provision for simultaneous release of fluid from the opposite end, whereby positive and controlled lifting and lowering of this end of the upper roll may be accomplished.

At' the outer end of the upper roll, the latch forms part of a drop head assembly 53 for freeing this end of the roll. to permit of removal of work. Such drop head assembly controls the movements of the latch at this end, and in addition to the latch, includes a pair of cylinders 55 and 57 interconnected adjacent their hottoms into a unitary assembly by a plate 59 having a passage 61 therein connecting the interiors of bothCylinders and providing a flow passage therebetween. The cylinder 55 is provided with trunnions 6.3, permitting said cylinders, as a unit, to be pivotally mounted between a pair of brackets 65 welded tothe end member 7 of the bass ame,-

A piston rod 67.. extending upwardly, from a piston 68 cylinder, 55 pivotally engages a yoke 69 having arms 71 which connect with the ends of the cross-bar 49 of the latch. The other, cylinder 57, which. may. be of shorter length, is provided at its. upper end with an air hose connection 73.

Both cylinders contain oil, and with the cylinder 57 connected to as'o-urce of compressed air, the admission of air under pressure will cause the transfer of oil from the shorter cylinder to the longer cylinder and thereby f r heriston nd, pis o d p d y w n the latch into latching position. So long as such air pressure is fmaintained againstthe oil, the latch will remain in its latching position, but upon removal of such-pressure, the combinedweight of the pistonvpiston rod and associated yoke acting through the moment arm provided by the arms '71, is sufiicient to withdraw the latch from its latching position and thereby free the outer end of the upper roll for the purpose previously indicated. The pivotal mounting of the two cylinders as a unitpermits of the necessary rocking of this unit in accomplishing the removal and resetting of the latch. A shoulder. stop 74 is maintained on the beariugblock to accurately determine the latching position of the cross-bar 49.

Acap 75 bolted to the .outer end of the upper roll and having a circumferential flange 77 facing the end or". the bearing blockand included bearing, serves to hold them captive, and precludes accidental removal thereof atany time. Thus the bearing remains assembledon theupper roll and there is' no need todisturb it even when freeing the outer end of the rolls for removal of work.

In the machine under consideration, rotational power is applied directly to the lower rolls only, and to effect such rotation, each of the lower rolls carries a gear 79 at its inner end, in mesh with a common drive pinion 81 mounted on the shaft 33 of a drive motor 85.

In order to facilitate the removal of work from the upper roll, provision is made for holding the upper roll in tilted position on its inner bearing support, following which the latch may be released.

For this purpose, the inner end of this roll is provided with an axial extension 87 of substantial length, the end of which may be engaged by a holding assembly 89 involving an inverted cylinder 91 supported on an arch 93 which in turn is fixed to a cross-member 9 incorporated into the base frame. This cylinder encloses a piston 97 slidably mounted therein and terminating externally of the cylinder in an exposed head 09 which is grooved to embrace the extremity of the upper roll extension. An oil line 101 connected to. the upper end of the cylinder permits of advancing the piston into contact with. the extension, following tilting of the upper roll on its inner end bearing. Restoration of the roll to its previous or lowered position occurs in response to permissible expulsion of fluid from the. cylinder due to the weight of the roll acting againstv the piston. The system for accomplishing the operation. of the, holding assembly is included in the overall hydraulic; system of the machine as depicted in Figure 14.

Such system involves a pump 102, preferably one of the variable volume type, which discharges into parallel connected lines 103, each in turn connectingwith the input opening of a fourway reversing, valve 104. Such valve is provided with a. pair of openings permitting of the. connection thereto of the previously identified pipe connections 51 and 52. A return line: 105 from the valve empties into a reservoir 106 from which the pump draws its. supply. A control handle' 10.7 on each such reversing valve, normally occupies a neutral. shut-off position, but may be shifted forwardly or in reverse to arbitrarily connect the lines 51 and 52 to-the, discharge and input of the pump.

Each half of the hydraulic system incorporates a hydraulic pressure booster circuit 108 involving a hydrau lically driven booster pump- 109 having its input connected. by: line 110; to the line 5t and its. exhaust to the return line 105 by a pipe connection; 111'. A. portion of the input to the'booster pump is;discharged-' at high pressure through. aline connection 112:.intothe line 51: leading to the upper endzof' the associated cylinder.

In the input line to the booster pump is a sequence valve 114' with.its:control end connected between the high pressure discharge line 112 of: the booster pumpand the booster pump exhaustline 111. Such sequence valve is a spring-seated valve normally. closing the inputline to the booster pump, with the springbeing. adjusted to open. said. valve-at a predetermined cut-in pressure developed in the line 51 to. the-upper end. of. the cylinder. A pilot-operated check valve 115 in theline 51 between the-input line 110to the booster pump: and: the booster highpressureline 112; with apilotzcontrol connection to the return line 52, serves to block the; line 51 at this point when held in closed position; and effectively, places the boosterpump in series withthemain pump 102: This check valve will normally remain ineffective, until the booster is about ready. to .cut. in.

The booster circuit as. thus. described and connected, can-functiononly on the downward or load, stroke of the associated piston, and its mode of operatiombriefiy, is as follows:

As the upper roll is lowered toward the work, the pressure required'is light and themain pump can function atmaximum output without the aid'of' the. booster pump, untilengagement of the roll with the, Workoccurs, at which moment the volume discharge ofthe main pump will'decrease as the pressure demands on the pump increase. Such increasing pressure appears at the control end of the sequence valve, and when it reaches, in value, the cut-in pressure adjustment of said valve, which may, for example, be of the order of 1,000 pounds per square inch the sequence valve will open and expose the input end of the booster pump to the fluid in the system, which then causes the pump end of the booster pump to discharge a portion of the fluid at high pressure, rising to the order of, say, 3000 pounds per square inch, into the feed line to the upper end of the associated cylinder as the bending operation proceeds to completion.

The control end of the sequence valve and the check valve, both being exposed to this increasingly higher pressure range, a holding circuit will be established for the sequence valve, while the check valve will be hydraulically locked to isolate the high pressure discharge of the booster pump from the lower pressure input and thus assure a series operation of the two pumps.

On the return or lift stroke of the pistons, the limitations as to speed of travel of the pistons are not nearly as critical as during the work stroke, and in order to speed up such return of the piston, the lower piston rod is preferably of greater diameter than the upper one in order to cut down the effective lift area of the piston. Thus, at any particular value of pressure demanded of the main pump, the lift speed of the piston will greatly exceed the rate of travel of the piston on the work stroke.

The tilt-maintaining piston 97 is hydraulically controlled from the main pump 102, through the pipe connection 101 to the cylinder 91. A manually operable valve 117 in this pipe connection enables the operator to control the flow of fluid into this cylinder to determine the rate of advance of the enclosed piston. When the desired extent of travel has been realized, the piston can be held in such position by closing off this valve.

As a safety factor, an upper limit of permissible back pressure in the cylinder and supply line may be established by a relief valve 118 disposed in the connection 101 and relieving back into a return line 105 of the system through a pipe connection 119. This relief valve is set to with- .stand any back pressure necessary to balance the upper roll in any tilted position, and open at pressure in excess thereof which could develop were one to raise the fulcrum or inner end of the roll while the piston 97 was in contact with the axial extension 87 of the roll. By manually relieving the pressure in the holding assembly cylinder 91, the upper roll may be lowered to its work position.

In utilizing a machine of the type described, the upper roll is adjustably spaced with respect to the lower rolls by an amount determined by the thickness of the sheet materia to be worked on and the degree of bending to be accomplished. Following insertion of the Work, the upper roll is brought to bear against the same While the lower rolls may be rotated to carry the Work further into the machine, the extent of such operations varying with the nature of the work.

in this connection, it is significant to note that during a bending operation, the stresses in the cradle end castings are self-contained, in that they are under squeeze between the work and the reactive pressure of the fluid in the cylinders. Consequently, such castings may be relatively light in weight.

To render the above described machine efficient, adjustments must be capable of being made not only quickly but at the same time, accurately. Incorporated in the machine for this purpose is an indicating means which serves not only to indicate the actual adjustment of each end of the upper roll with respect to the lower rolls, but also the relative adjustment of each end with respect to the other. Such indicating means includes a pair of indicating wheels 123, 125 disposed side by side within a housing 127, and having their rims similarly graduated. The housing has a front opening exposing the indicating wheels to view. A cross-strip 129 afiixed to opposite edges of this opening, serves as a reference in taking readings from said indicating wheels.

In order to register adjustments of the upper roll, each of the indicating wheels is caused to rotate in accordance with movement of one end of such upper roll, and this is made possible by converting the linear movement of the roll-adjusting pistons into rotational movement of the indicator wheels. In this connection, each indicating wheel has a sprocket 131 afiixed thereto and each of the pistons 33 at its exposed end has bolted thereto, a torque arm 133.

A shaft 1.3L journalled in bearings bolted to the frame end member 9 and a cross-member 137, has a pair of sprockets 13%, 139 mounted thereon, the sprocket 136 being in alignment with the sprocket 131 associated with one of the indicating wheels, while the sprocket 139 is disposed in alignment with a point on one of the torque arms.

A chain 141 having one end bolted to said torque arm, passes over the aligned sprocket 139 and is anchored thereto. A second chain 143 having one end anchored to the sprocket 136, is draped over the aligned indicator wheel sprocket and terminates in a freely suspended weight 145.

The coupling between the remaining indicating wheel and the second torque arm is similar in nature and involves a shaft 147 journalled in bearings carried by crossframe members 137, 149 and 151. This shaft has mounted thereon a pair of sprockets 153, 155, the sprocket 153 having a sprocket chain 157 anchored at one end thereto and draped over the aligned indicator wheel sprocket to hold a freely suspended weight B9, while a second sprocket chain 161 bolted at one end to the other torque airsm, has its remaining end anchored to the aligned sprocket Within the adjusting range of the machine, the sprockets are designed to make less than one complete revolution, and in anchoring the chains 141 and 161 to their respective shaft sprockets, the points of attachment must be such as to permit wrapping of the chains Without overlap, as the corresponding chains at the other shaft sprockets unwind, and vice versa.

By setting both indicating wheels to the same indication for a parallel disposition of the upper roll, the upper roll may thereafter be adjusted quickly and accurately, for not only parallel operation, but for coning operations which call for a slight angular tilt of the upper roll with respect to the lower rolls.

All controls along with the indicating wheels are assembled at a single operators station 163 where the entire control of the machine is in the hands of one man while another handles the work. With the indicating wheels and controls before him, he is in position to quickly ad ust the upper roll to meet any work requirements, whether it involve rolling the work to a cylindrical form or a conical form; and following the removal of such work from the machine, the operator may accurately and quickly reset the upper roll to its previous adjusted position, or any other desired position.

The use of hydraulic power in adjusting the upper roll permits of rapid movement of such roll to a desired positron and, with the use of the indicating wheels to guide the operator, he can take full advantage of the speed which such hydraulic control ofiers.

From the above description of the invention in its preferredfonm, it will be apparent that the same fulfills all the ob ects of the invention previously listed, and while the invention has been illustrated and described in considerable detail, the same is subject to alteration and modificatron without departing from the underlying principles nvolved, and, accordingly, protection should not be limited to the specific details illustrated and described except as may be necessitated by the appended claims.

I claim:

1. In a bending machine, a base frame, end supports mounted on said base frame in spaced relationship to each other, a pair of rolls journalled in and between said end supports, means associated with said end supports and providing support for an upper roll, each said means involving a vertically adjustable rod, a cross pin supported on said rod, a bearing block and included bearing removably resting on said pin and having a complementary groove in its lower edge to seat said pin and enable the same to carry an end of said upper roll and permit pivotal movement of said bearing block, latch means for holding said block and bearing on said cross pin, and means for selectively control-ling the movement of said vertically adjustable rods whereby to determine the spacing between said lower rolls and the ends of said upper roll.

2. In a bending machine, a base frame, end supports mounted on said base frame in spaced relationship to each other, a pair of rolls journalled in and between said end supports, means associated with said end supports and providing support for an upper roll, each said means involving a vertically adjustable rod, a cross head mounted on the upper end of said vertically adjustable rod and involving a pair of vertically disposed parallel arms and a cross pin supported by and between said arms, a bearing block resting on said pin and having a complementary groove in its lower edge to seat said pin, and an upper surface contoured on an are having its center of curvature at the axis of said pin, a bearing in said block, latch means for pivotally holding said block and bearing on said pin, said latch means involving a pair of links swingably mounted on the end of said pin and having their free ends interconnected by a cross bar provided with a complementary arcuate lower surface adapting said bar to slidably fit the upper arcuate surface of said bearing block, and means for selectively controlling the vertical adjustment of said rods whereby to determine the spacing between said lower rolls and the ends of said upper roll.

3. In a bending machine, a base frame, a pair of cradle end castings spanning said base frame in spaced relation ship to each other, a pair of rolls cradled in and between said end castings, means associated with each of said cradle end castings and providing support for an upper roll, each said means involving a vertically adjustable rod, a cross head mounted on the upper end of said vertically adjustable rod and involving a pair of vertically disposed parallel arms and a cross pin supported by and between said arms, a bearing block resting on said pin and having a complementary groove in its lower edge to seat said pin, and an upper surface contoured on an are having its center of curvature at the axis of said pin, a bearing in said block, latch means for pivotally holding said block and bearing on said pin, said latch means involving a pair of links swingably mounted on the ends of Said pin and having their free ends interconnected by a cross bar provided with a complementary arcuate lower surface adapting said bar to slidably fit the upper arcuate surface of said bear-ing block, and means for selectively controlling the movement of said vertically adjustable rods whereby to determine the spacing between said lower rolls and the ends of said upper roll.

4. In a bending machine, a base frame; a pair of cradle end castings spanning said base frame in spaced relationship to each other, a pair of rolls cradled in and between said end castings, hydraulically operable piston means associated with each of said cradle end castings and providing support for an upper roll, each said hydraulic operable piston means involving a cylinder integral with and depending from an end casting, a double acting piston in said cylinder, a piston rod extending upwardly from the upper side of said piston, a hydraulic line connection to said cylinder above the upper end of the stroke of said piston and a hydraulic line connection to said cylinder below the lower end of the stroke of said piston, means for selectively controlling the movement of said pistons whereby to determine the spacing between said lower rolls and the ends of said upper roll.

5. In a bending machine, a base frame, a pair of cradle end castings spanning said base frame in spaced relationship to each other, a pair of rolls supported by and between said end castings, and means associated with said end castings for supporting an upper roll, each of said last means involving a vertically adjustable rod, a cross head mounted on the upper end of said vertically adjustable rod and involving a pair of vertically disposed parallel arms and a cross pin supported by and between said arms, a bearing block having a groove in its lower surface for said block to seat said pin and rest thereon, and an upper surface contoured on an arc having its center of curvature at the axis of said pin, a bearing in said block, latch means for pivotally holding said block and bearing on said pin, said latch means involving a pair of links swingably mounted on the ends of said pin and having their free ends interconnected by a cross bar provided with an arcuate lower surface complementary to the upper surface of said bearing block, thus adapting said bar to slidably fit the upper arcuate surface of said bearing block.

6. In a bending machine involving a plurality of rolls between which work is fed to effect bending of such work, means at each end of one of said rolls for adjusting said roll with respect to the others, said means comprisinlg a vertically adjustable rod extending toward and supporting an end of said roll and a second rod extending in the opposite direction; and means for indicating both the actual adjustment of each end of said roll and the relative adjustment of each end with respect to the other, said indicating means including a pair of like indicating wheels disposed side by side and having their rims similarly graduated, each of said wheels having a sprocket aflixed thereto for rotation with its associated wheel, and means coupling each wheel to one of said sec- 0nd rods for converting linear movement of each such second rod into rotational movement of its associated indicating wheel.

7. In a bending machine involving a plurality of rolls between which work is fed to effect bending of such work, means at each end of one of said rolls for adjusting said roll with respect to the others, said means comprising a vertically adjustable rod extending toward and supporting an end of said roll and a second rod extending in the opposite direction; and means for indicating both the actual adjustment of each end of said roll and the relative adjustment of each end with respect to the other, said indicating means including a pair of like indicating wheels disposed side by side and having their rims similarly graduated, each of said wheels having a sprocket afiixed thereto for rotation with its associated wheel, and means coupling each wheel to one of said second rods for converting linear movement of each such second rod to rotational movement of its associated indicating wheel, said means including a shaft having a pair of sprockets, a sprocket chain connected at one end to one of said shaft sprockets and at its other end to one of said second rods, and a second sprocket chain draped over the associated wheel sprocket and connected at one end to'the other of said shaft sprockets and at its other end terminating in a freely suspended weight.

8. Ina bending machine utilizing a pair of lower rolls and an upper roll, a drop head assembly for the outer end of the upper roll comprising a support below said end; a bearing block and included bearing mounted on the outer end of said upper roll and resting on said support; latch means for subsequently removably securing said bearing block 'on said support; and means for controlling the movement of said latch means to and from latching position while said bearing block remains on its support.

9. In a bending machine utilizing a pair of lower rolls and an upper roll, a drop head assembly for the outer end of the upper roll comprising an adjustable support below said end; a bearing-block and included bearing mounted on the outer end of said'upper roll and having its upper surfacearced; latch means for removably securing said 'bearingvblock on said support, said latch means involving a pair of links pivotally connected to said support and a cross bar interconnecting the free ends of said links, said cross bar having its lower surface correspondingly arced to permit of said bar sliding over said bearing block; and means for controlling the movement of said latch means to and from latching position, said controlling means including a pair of cylinders interconnected adjacent their bottoms by a passage, means pivotally mounting said cylinders as a unit, a piston in one of said cylinders having an upwardly extending piston rod, a pair of links connecting said piston rod to the upper end of said latch means, liquid in said cylinders, means for introducing air under pressure into said other cylinder above the liquid therein to swing said latching means into latching position, said piston, piston rod and link connection being of suificient weight to withdraw said latching means in the absence of air pressure in said one cylinder.

10. In a bending machine utilizing a pair of lower rolls and an upper roll, a drop head assembly for the outer end of the upper roll comprising an adjustable support below said end, said support including a crosshead mounted on the upper end thereof and involving a pair of vertically disposed parallel arms, and a cross pin supported by and between said arms; a bearing block and included bearing mounted on the outer end of said upper roll, said bearing block having a transverse groove in its lower surface providing a substantially complementary fit with said cross pin when resting thereon, and its upper surface arced about said pin as a center of curvature; latch means for removably securing said bearing block on said support, said latch means involving a pair of links pivotally connected adjacent the ends of said pin, and a cross bar interconnecting the free ends of said links, said cross bar having its lower surface arced about said pin as a center of curvature to permit of said bar sliding over said bearing block; and means for controlling the move ment of said latch means to and from latching position, said latch controlling means including a pair of cylinders interconnected adjacent their bottoms by a passage, means pivotally mounting said cylinders as a unit, a piston in one of said cylinders having an upwardly extending piston rod, a pair of links connecting said piston rod to the upper end of said latch means, liquid in said cylinders, means for introducing air under pressure into said other cylinder above the liquid therein to swing said latching means into latching position, said piston, piston rod and link connection being of sufiicient weight to withdraw said latching means in the absence of air pressure in said one cylinder.

11. In a bending machine utilizing a pair of lower rolls and an upper roll, a drop head assembly for the outer end of the upper roll comprising a hydraulically adjustable support below said end, said support involving a cylinder, a piston in said cylinder having a piston rod extending upwardly therefrom, a crosshead mounted on the upper end of said upwardly extending piston rod and involving a pair of vertically disposed parallel arms, and a cross pin supported by and between said arms; a bearing block and included bearing mounted on the outer end of said upper roll, said bearing block having a transverse groove in its lower surface providing a substantially complementary fit with said cross pin when resting thereon, and its upper surface arced about said pin as a center of curvature; latch means for removably securing said bearing block on said support, said latch means involving a pair of links pivotally connected adjacent the ends of said pin, and a cross bar interconnecting the free ends of said links, said cross bar having its lower surface arced about said pin as a center of curvature to permit of said bar sliding over said bearing block; and means for controlling the movement of said latch means to and from latching position, said controlling means including a pair of cylinders interconnected adjacent their bottoms by a passage, means pivotally mounting said cylinders as a unit, a piston in one of said cylinders having an upwardly extending piston rod, a pair of links connecting said piston rod to the upper end of said latch means, liquid in said cylinders, means for introducing air under pressure into said other cylinder above the liquid therein to swing said latching means into latching position, said piston, piston rod and link connection being of sufficient weight to withdraw said latching means in the absence of air pressure in said one cylinder.

12. In a bending machine, a roll, and a pivotally mounted bearing assembly for an end of said roll, said pivotally mounted bearing assembly comprising a support for said end of the roll and including a cross-pin, a bearing block having a groove in its lower surface substantially complementary to the surface of said cross-pin, a bearing in said bearing block, said bearing block and included bearing being mounted on said end of the roll and pivotally resting on said cross-pin, and latching means for holding said bearing block on said cross-pin.

13. In a bending machine, a roll, and a pivotally mounted bearing assembly for an end of said roll, said pivotally mounted bearing assembly comprising a support for said end of the roll and including a cross-pin, a bearing block having a groove in its lower surface substantially complementary to the surface of said cross-pin, a bearing in said bearing block, said bearing block and included bearing being mounted on said end of the roll and pivotally resting on said cross-pin, and latching means for holding said bearing block on said cross-pin, said latching means including a link mounted at each end of said pin. and cross-bar connecting the free ends of said links, said links being a length permitting said cross-bar to swing over said bearing block and contact the upper surface thereof, both said bearing block surface and the contacting surface of said cross-bar being arced on a center of curvature coinciding with the axis of said cross-pin.

14. In a bending machine, a base frame, end supports on said base frame in spaced relationship to each other, a roll journalled in said end supports, hydraulically operable piston means associated with each of said end supports and providing support for an upper roll, each of said hydraulically operable piston means involving a cylinder carried by its associated end support, a piston in said cylinder, a piston rod extending upwardly from the upper side of said piston, a bearing block, and means for mounting the same on said piston rod, an upper roll journalled in said bearing blocks and supported by said piston rods, and means for latching said upper roll bearing blocks to said hydraulically operable piston means, said latch means being removable while maintaining said upper roll supported by said piston rods.

15. In a bending machine, a base frame, a pair of end supports spanning said base frame in spaced relationship to each other, a pair of rolls supported by said end supports, hydraulically operable piston means associated with each of said end supports and providing support for an upper roll, each said hydraulic operable piston means involving a cylinder carried by an end support, a double acting piston in said cylinder, a hydraulic connection on said cylinder above the upper end of the stroke of said piston and a hydraulic connection on said cylinder below the lower end of the stroke of said piston, and means exposing a large area on the upper side of said piston to the upper hydraulic connection and a smaller area on the underside of said piston to the lower hydraulic connection to provide a faster movement of said piston in the up direction than in the down direction.

16. In a bending machine, a base frame, a pair of end supports spanning said base frame in spaced relationship to each other, a pair of rolls supported by said end supports, hydraulically operable piston means associated with each of said end supports and providing support for an upper roll, each said hydraulic operable piston means involving a cylinder carried by an end support, a double acting piston in said cylinder, a hydraulic connection on said cylinder above the upper end of the stroke of said piston and a hydraulic connection on said cylinder below 1 1 the lower end of the stroke of said piston, and means expo s'in'g a'large are'at-on the upper side of said piston to the ufiper hydraulic connection and 2i srnaill'e'r area on the underside of said piston to th' lower hydraulic connec- 11611 to provide at faster movement of said fiist'on in the 5 up direction than in the down direetion, said nieans inciuciin 21 51115611 rod (if one diameter extending upwardly from the upper side of said piston, and a piston rod of reater diameter cit-ending dwfiwardl from the under side of said piston 10:

Referenes' Cited in the file of this paltent UNITED STATES PATENTS 661,459 511151 er a1. Nov. 6, 1900 15 12 Dec. 5, Lindg-ren Mar. 18, 1924 Smith Aug. 4,- 1925 Trosch Feb. 1 9,- 1929 Johnston July 5, 1938 Tinley et a1. Oct. 2, 1951 FOREIGN PATENTS Austria June 10, 1914 Germany May 4, 1926 Great Britain July 11, 1929 Germany Sept 5, 1935 

